elf: clean up fill_note_info()

Introduce a helper function elf_note_info_init() to help fill_note_info()
to do initializations, also fix the potential memory leaks.

[[e-mail]: remove NUM_NOTES]
Signed-off-by: WANG Cong <[e-mail]>
Cc: Alexander Viro <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: Roland McGrath <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/binfmt_elf.c

···
 	int numnote;
 };
 
-static int fill_note_info(struct elfhdr *elf, int phdrs,
-			  struct elf_note_info *info,
-			  long signr, struct pt_regs *regs)
+static int elf_note_info_init(struct elf_note_info *info)
 {
-#define	NUM_NOTES	6
-	struct list_head *t;
-
-	info->notes = NULL;
-	info->prstatus = NULL;
-	info->psinfo = NULL;
-	info->fpu = NULL;
-#ifdef ELF_CORE_COPY_XFPREGS
-	info->xfpu = NULL;
-#endif
+	memset(info, 0, sizeof(*info));
 	INIT_LIST_HEAD(&info->thread_list);
 
-	info->notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote),
-			      GFP_KERNEL);
+	/* Allocate space for six ELF notes */
+	info->notes = kmalloc(6 * sizeof(struct memelfnote), GFP_KERNEL);
 	if (!info->notes)
 		return 0;
 	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
 	if (!info->psinfo)
-		return 0;
+		goto notes_free;
 	info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
 	if (!info->prstatus)
-		return 0;
+		goto psinfo_free;
 	info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
 	if (!info->fpu)
-		return 0;
+		goto prstatus_free;
 #ifdef ELF_CORE_COPY_XFPREGS
 	info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
 	if (!info->xfpu)
-		return 0;
+		goto fpu_free;
 #endif
+	return 1;
+#ifdef ELF_CORE_COPY_XFPREGS
+ fpu_free:
+	kfree(info->fpu);
+#endif
+ prstatus_free:
+	kfree(info->prstatus);
+ psinfo_free:
+	kfree(info->psinfo);
+ notes_free:
+	kfree(info->notes);
+	return 0;
+}
 
-	info->thread_status_size = 0;
+static int fill_note_info(struct elfhdr *elf, int phdrs,
+			  struct elf_note_info *info,
+			  long signr, struct pt_regs *regs)
+{
+	struct list_head *t;
+
+	if (!elf_note_info_init(info))
+		return 0;
+
 	if (signr) {
 		struct core_thread *ct;
 		struct elf_thread_status *ets;
···
 #endif
 
 	return 1;
-
-#undef NUM_NOTES
 }
 
 static size_t get_note_info_size(struct elf_note_info *info)